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From: "Paul.B.Andersen" <relativity@paulba.no>
Newsgroups: sci.physics.relativity
Subject: Re: Space-time interval (2)
Date: Thu, 15 Aug 2024 12:22:22 +0200
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Den 14.08.2024 19:43, skrev Richard Hachel:
> Le 14/08/2024 à 19:33, "Paul.B.Andersen" a écrit :
>> Den 14.08.2024 00:01, skrev Richard Hachel:
> 
>> STOP FLEEING AND ADDRESS THE ISSUE!
> 
> I am not running away.

You are fleeing like hell.

> Your problem simply does not make sense.
> You are talking to me about planes that fly at Galilean speeds, asking 
> me to respond with relativistic considerations.

What a nonsensical statement.
Do you remember this scenario which you never responded to:

The triplets Ginette, Elise and Wanda are co-located on
the equator. They all have an atomic clock.

Ginette are always stationary on the Equator.
Elise is travelling eastwards at low altitude in an aeroplane.
Wanda is travelling westwards at low altitude in an aeroplane.
Both are travelling once around Earth at equator.

Note that the altitude is so low that the gravitational
blue shift can be ignored.

 From the time they are co-located, to they again are co-located
after Elise's and Wanda's journey, Ginette's clock shows that
the duration of their journey is τ_G = two sidereal days.

Please find what the duration of the journey will be
measured by Elise and Wanda, τ_E and τ_W.

Some data:
Circumference of Earth at equator L = 40075 km
Sidereal day Tday = 86164.0905 s
Ginette's speed in the non rotating Earth centred frame of reference 
(ECI frame), v = L/Tday = 465.1 m/s

SR predicts:  τ_E − τ_G = −259.2 ns,  τ_W − τ_G = +155.5 ns

The point is that the aeroplanes are moving at what you call
"Galilean speeds", and yes, in the real world it is possible
to make "relativistic consideration" at those speeds.
You can even measure the "relativistic phenomena" with real clocks.
And it is done in the real world.

https://paulba.no/paper/Hafele_Keating.pdf
https://paulba.no/paper/Alley.pdf
(see pages 708-716)

> What can I answer you?

You can answer the questions.

But the issue isn't "relativistic consideration",
it is about synchronisation of clocks!
=========================================

|> Den 22.07.2024 21:37, skrev Paul.B.Andersen:
|>>
|>> You know of course that all clocks in the same time zone
|>> are synchronous. In France and Norway clocks are currently
|>> showing GMT + 2 hour, so my clock and your clock are actually
|>> synchronous.
|>>
|>> Please explain why our clocks are NOT synchronous.
|>> (To within few seconds|

|> Den 22.07.2024 23:55, Richard Hachel responded:>
|>> But I keep explaining it to you.
|>>
|>> This is a property of space that can be called universal anisochrony.
|>>
|>> This does not translate into the idea that the “plan of present time”
|>> so dear to physicists does not exist, it is a thought that seems
|>> logical to them, but it is an abstract thought.
|>>

STOP FLEEING AND ADDRESS THE ISSUE!

Let's assume that both clocks show UTC + 2h within a second.

I leave Oslo Airport (Gardemoen Airport) when the watch on
the airport shows 12.00.00 ± 1 s
I arrive at Paris Airport (Charles De Gaulle Airport) when
the watch on the airport shows 13.30.32 ± 1 s.
The difference is T = 1h 30m 32 ± 2 s
The distance in the ground frame between the airports is
L = 1358.03 ± 0.1 km
v = T/L = 250.01 ± 0.11 m/s = 900.0 ± 0.4 km/h

Question #1:
------------
Is the time T = 1h 30m 32 ± 2 s
the correct time (temporal interval) measured in
the ground frame, between the events "Departure from Oslo"
and "Arrival in Paris"?

Question #2:
------------
Is the speed v = 900.0 ± 0.4 km/h
the correct speed of the aeroplane, measured in the ground frame?


The point is that if the clocks in Oslo and Paris are not
synchronous within a second, you have to answer "no" to both
questions.

So what are your answers to the simple questions?

I bet you will keep fleeing. Chicken! :-D

> 
> R.H.

-- 
Paul

https://paulba.no/